English
For a finite index set ι' and a function f: ι' → M, the decomposition distributes over finite sums: decompose(∑ f i) = ∑ decompose(f i).
Русский
Разложение распределяется по конечной сумме: decompose(∑ f(i)) = ∑ decompose(f(i)).
LaTeX
$$$\mathrm{decompose}_{\mathcal{M}}\Big(\sum_{i\in s} f(i)\Big) = \sum_{i\in s} \mathrm{decompose}_{\mathcal{M}}(f(i))$$$
Lean4
@[simp]
theorem decompose_symm_add (x y : ⨁ i, ℳ i) :
(decompose ℳ).symm (x + y) = (decompose ℳ).symm x + (decompose ℳ).symm y :=
map_add (decomposeAddEquiv ℳ).symm x y